Implantable medical devices include devices such as stents and stent grafts, vascular grafts and valves, heart valves, artificial hearts, joint and bone implants, vascular filters, and the like. In order to locate the implant accurately both during and after implantation, it is important to be able to visualize the implant using non-invasive methods such as x-ray detection. This, in turn, requires that the implant itself be radiopaque. Although some materials such as cobalt-chromium alloys are both suitable for implants and absorb x-rays, rendering them inherently radiopaque, many others are not. In particular, bioerodible materials such as polymers, iron, or magnesium that would otherwise be suitable are radiolucent, rather than inherently radiopaque. Moreover, ultrathin implants may be radiolucent even if they include heavy elements that would otherwise render them radiopaque because the x-ray attenuation length is not sufficiently long. To address this issue, a number of solutions have been proposed, including forming alloys that include one or more x-ray absorbing elements (e.g., platinum, gold, or palladium), and providing the implants with x-ray absorbing markers.